Manhattan parade goers display both American and Nazi flags in 1939.

A parade in New York City–what could be lovelier? Except this parade, which took place in Upper Manhattan in 1939, was a rally held by the German-American Bund organization to show support for Hitler’s Nazi Germany. As shocking as it may seem now, marchers carried both American and Nazi flags through city streets. Mayor Fiorello La Guardia denounced the parade and attendance was limited. But the group’s rally in Madison Square Garden in February 1939 reportedly drew 20,000. During that event, President Franklin D. Roosevelt was mocked and called “Frank D. Rosenfeld.” The German-American Bund ceased to exist soon after the bombing of Pearl Harbor, but it left a hateful if largely forgotten mark on the city.